Aberrant Nodal Topological Properties and Functional Connectivity of Amygdala Subregions Underlie Emotion-Visceral
Yidan Liang1,2, Rongting Hou1,2, Liqiang Wu1,2
1School of Clinical Medicine, The Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China, hznu.edu.cn.
Background:
Irritable bowel syndrome (IBS) is a common disorder of brain-gut interaction frequently co-occurs with depressive symptoms (dIBS). The amygdala is a critical hub for emotion-visceral integration and exhibits functional heterogeneity across its subregions. However, subregion-specific network alterations in dIBS remain unclear.
Methods:
Forty-nine IBS patients and 36 demographically matched healthy controls (HCs) completed resting-state functional magnetic resonance imaging (rs-fMRI) and clinical assessments. Patients were stratified into dIBS (n = 28) and nondepressive IBS (ndIBS, n = 21) groups. Bilateral lateral amygdala (lAmyg) and medial amygdala (mAmyg) were selected as seeds for graph-theoretical nodal metrics and seed-based functional connectivity (FC) analyses. One-way analysis of covariance with post hoc comparisons was performed to assess intergroup differences. Correlation, mediation, and receiver operating characteristic (ROC) analyses were further conducted.
Results:
Compared with ndIBS patients, dIBS patients exhibited increased degree centrality (DC) and nodal efficiency (Ne) in the left lAmyg, which were positively associated with depressive symptom severity. In addition, dIBS patients showed widespread hypoconnectivity between amygdala subregions and prefrontal and sensorimotor regions, including the medial superior frontal gyrus, postcentral gyrus, and thalamus. These FC alterations were correlated with clinical symptoms severity. Notably, the mAmyg-related FC in superior frontal gyrus and thalamus showed mediation effects linking gastrointestinal symptoms and depressive symptoms and exhibited high accuracy in distinguishing dIBS from ndIBS (area under the curves, AUCs > 0.8).
Conclusion:
Aberrant nodal properties and disrupted connectivity of amygdala subregions may reflect altered emotion-visceral integration in dIBS. These findings provide neuroimaging evidence for brain-gut interaction abnormalities in dIBS and suggest that amygdala subregional networks may serve as potential markers for symptom stratification and targeted interventions.
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